51 research outputs found

    Targeted optogenetic stimulation to study the computational properties in neuronal ensembles recorded by multi-electrode devices

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    Micro-electrode array (MEA) technology has been exploited as a powerful tool for providing distributed information on learning, memory and information processing in cultured neuronal tissue, enabling an experimental perspective from the single cell level up to the scale of complex biological networks. An integral part in the use of MEAs involves the need to apply a local stimulus to stimulate or modulate the activity of certain regions of the tissue down to the single neuron level. Currently, this presents various limitations due to the low spatial resolution of the electrical stimulation. The recent development of optogenetic probes enables for the opportunity to switch from a full electrical paradigm to a combination of a reliable optical stimulation, including excitation and inhibition, coupled to large scale recordings based on MEA. In order to take full advantage from the expression of such optical tools, the capability of properly shaping the optical stimulation pattern has to be developed to fit at the same time either the single neuron targeting or multi site/large area stimulation. The design of a versatile patterned light projection device is an essential step towards this goal. Digital micro-mirrors devices (DMDs) spatial light modulators became recently available a tools for spatial mapped fluorescence measurements, photo-patterning, molecule uncaging and high resolution imaging. Here we describe a two-wavelength spatial light projection system for real-time closed loop modulation of neuronal activity, which is able to trigger a specific protocol of optical stimulation (space, time, wavelengths) by properly configuring the DMD upon detection of typical patterns (space and time) of electrical activation recorded with MEA. By adopting such an approach, it will be possible to better understand the fundamental mechanisms underlying the propagation and processing of the information in distinct neuronal subareas or subpopulations and their specific roles within in-vitro or ex-vivo neuronal networks

    Canine pseudopregnancy: an evaluation of prevalence and current treatment protocols in the UK

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    Background: There is a dearth of literature on pseudopregnancy in the bitch, with only a few treatment-based studies published since the 1990s. Pseudopregnancy may be under-recognised in bitches and may account for a proportion of behavioural cases seen in veterinary practices including aggression. Little is known about commonly used treatments for overtly pseudopregnant bitches and it is possible that current regimes may not be prescribed for a sufficient duration to control any clinical signs including, physical and behavioural changes. To investigate current trends in diagnosis and treatment of canine pseudopregnancy, a postal survey was sent to 2000 randomly selected veterinary surgeons in UK veterinary practices. The questionnaire queried how often vets recognise cases of pseudopregnancy in spayed and entire bitches, which physical or behavioural signs are commonly recognised for diagnosis, and which management or treatment protocols are used. Results: The response rate was 19.8% (397/2000). Ninety-six percent of veterinary surgeons reported seeing pseudopregnant bitches showing behavioural changes without any physical changes within the last 12 months. Of those behavioural changes, collecting and mothering objects was the most frequently reported behavioural sign (96%). Ninety-seven percent of vets had seen aggression in pseudopregnant bitches. Nevertheless, only 52% of vets routinely asked owners about behavioural changes during consultations. Forty-nine percent of respondents reported seeing pseudopregnancy in spayed bitches. The most commonly reported physical sign was enlarged mammary glands and/or milk production (89%). Treatment options varied (surgical, medical or none) and depended on duration and severity of physical and behavioural signs, owners’ preference, cost, concurrent disease, drug availability and previous history. Conclusions: This is the largest epidemiological study of canine pseudopregnancy in the UK. The prevalence and severity of clinical signs in dogs with pseudopregnancy are variable and possibly under-estimated. Dogs with overt pseudopregnancy experience diverse physical and behavioural changes and information on standard treatment protocols are lacking. Although, progress on our understanding of diagnosis and treatment of pseudopregnancy in spayed and entire bitches has been made, further studies are warranted

    Severity of oEsophageal Anastomotic Leak in patients after oesophagectomy: the SEAL score

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    \ua9 The Author(s) 2022. Published by Oxford University Press on behalf of BJS Society Ltd. BACKGROUND: Anastomotic leak (AL) is a common but severe complication after oesophagectomy. It is unknown how to determine the severity of AL objectively at diagnosis. Determining leak severity may guide treatment decisions and improve future research. This study aimed to identify leak-related prognostic factors for mortality, and to develop a Severity of oEsophageal Anastomotic Leak (SEAL) score. METHODS: This international, retrospective cohort study in 71 centres worldwide included patients with AL after oesophagectomy between 2011 and 2019. The primary endpoint was 90-day mortality. Leak-related prognostic factors were identified after adjusting for confounders and were included in multivariable logistic regression to develop the SEAL score. Four classes of leak severity (mild, moderate, severe, and critical) were defined based on the risk of 90-day mortality, and the score was validated internally. RESULTS: Some 1509 patients with AL were included and the 90-day mortality rate was 11.7 per cent. Twelve leak-related prognostic factors were included in the SEAL score. The score showed good calibration and discrimination (c-index 0.77, 95 per cent c.i. 0.73 to 0.81). Higher classes of leak severity graded by the SEAL score were associated with a significant increase in duration of ICU stay, healing time, Comprehensive Complication Index score, and Esophagectomy Complications Consensus Group classification. CONCLUSION: The SEAL score grades leak severity into four classes by combining 12 leak-related predictors and can be used to the assess severity of AL after oesophagectomy

    Social factors affecting seasonal variation in bovine trypanosomiasis on the Jos Plateau, Nigeria

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    BACKGROUND: African Animal Trypanosomiasis (AAT) is a widespread disease of livestock in Nigeria and presents a major constraint to rural economic development. The Jos Plateau was considered free from tsetse flies and the trypanosomes they transmit due to its high altitude and this trypanosomiasis free status attracted large numbers of cattle-keeping pastoralists to the area. The Jos Plateau now plays a major role in the national cattle industry in Nigeria, accommodating approximately 7% of the national herd, supporting 300,000 pastoralists and over one million cattle. During the past two decades tsetse flies have invaded the Jos Plateau and animal trypanosomiasis has become a significant problem for livestock keepers. Here we investigate the epidemiology of trypanosomiasis as a re-emerging disease on the Plateau, examining the social factors that influence prevalence and seasonal variation of bovine trypanosomiasis. METHODS: In 2008 a longitudinal two-stage cluster survey was undertaken on the Jos Plateau. Cattle were sampled in the dry, early wet and late wet seasons. Parasite identification was undertaken using species-specific polymerase chain reactions to determine the prevalence and distribution of bovine trypanosomiasis. Participatory rural appraisal was also conducted to determine knowledge, attitudes and practices concerning animal husbandry and disease control. RESULTS: Significant seasonal variation between the dry season and late wet season was recorded across the Jos Plateau, consistent with expected variation in tsetse populations. However, marked seasonal variations were also observed at village level to create 3 distinct groups: Group 1 in which 50% of villages followed the general pattern of low prevalence in the dry season and high prevalence in the wet season; Group 2 in which 16.7% of villages showed no seasonal variation and Group 3 in which 33.3% of villages showed greater disease prevalence in the dry season than in the wet season. CONCLUSIONS: There was high seasonal variation at the village level determined by management as well as climatic factors. The growing influence of management factors on the epidemiology of trypanosomiasis highlights the impact of recent changes in land use and natural resource competition on animal husbandry decisions in the extensive pastoral production system

    ICAR: endoscopic skull‐base surgery

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    Brain size regulations by cbp haploinsufficiency evaluated by in-vivo MRI based volumetry

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    The Rubinstein-Taybi Syndrome (RSTS) is a congenital disease that affects brain development causing severe cognitive deficits. In most cases the disease is associated with dominant mutations in the gene encoding the CREB binding protein (CBP). In this work, we present the first quantitative analysis of brain abnormalities in a mouse model of RSTS using magnetic resonance imaging (MRI) and two novel self-developed automated algorithms for image volumetric analysis. Our results quantitatively confirm key syndromic features observed in RSTS patients, such as reductions in brain size (-16.31%, p < 0.05), white matter volume (-16.00%, p < 0.05), and corpus callosum (-12.40%, p < 0.05). Furthermore, they provide new insight into the developmental origin of the disease. By comparing brain tissues in a region by region basis between cbp(+/-) and cbp(+/+) littermates, we found that cbp haploinsufficiency is specifically associated with significant reductions in prosencephalic tissue, such us in the olfactory bulb and neocortex, whereas regions evolved from the embryonic rhombencephalon were spared. Despite the large volume reductions, the proportion between gray-, white-matter and cerebrospinal fluid were conserved, suggesting a role of CBP in brain size regulation. The commonalities with holoprosencephaly and arhinencephaly conditions suggest the inclusion of RSTS in the family of neuronal migration disorders.We are grateful to Begona Fernandez for her excellent technical assistance. We would like to thank S. Sawiak (Wolfson Imaging Centre, University of Cambridge, Cambridge, United Kingdom) for the mouse brain tissue probability maps and the SPMmouse plug-in, and to N. Kovacevic (Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada) for the atlas of the mouse brain. Supported by grants from the Spanish MINECO to S.C. (BFU 2012-39958) and MINECO and FEDER to D.M. (TEC 2012-33778) and from MINECO (SAF2011-22855) and Generalitat Valenciana (Prometeo/2012/005) to A.B. The Instituto de Neurociencias is "Centre of Excellence Severo Ochoa".Ateca Cabarga, JC.; Cosa, A.; Pallares, V.; Lopez-Atalaya, JP.; Barco, A.; Canals, S.; Moratal PĂ©rez, D. (2015). Brain size regulations by cbp haploinsufficiency evaluated by in-vivo MRI based volumetry. Scientific Reports. 5. https://doi.org/10.1038/srep16256S5Rubinstein, J. H. & Taybi, H. Broad thumbs and toes and facial abnormalities. A possible mental retardation syndrome. Am J Dis Child 105, 588–608 (1963).Van Belzen, M., Bartsch, O., Lacombe, D., Peters, D. J. & Hennekam, R. C. Rubinstein-Taybi syndrome (CREBBP, EP300). Eur J Hum Genet. 19, preceeding 118–120 (2011).Hennekam, R. C. 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    Allelic exclusion of the immunoglobulin heavy chain locus is independent of its nuclear localization in mature B cells

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    In developing B cells, the immunoglobulin heavy chain (IgH) locus is thought to move from repressive to permissive chromatin compartments to facilitate its scheduled rearrangement. In mature B cells, maintenance of allelic exclusion has been proposed to involve recruitment of the non-productive IgH allele to pericentromeric heterochromatin. Here, we used an allele-specific chromosome conformation capture combined with sequencing (4C-seq) approach to unambigously follow the individual IgH alleles in mature B lymphocytes. Despite their physical and functional difference, productive and non-productive IgH alleles in B cells and unrearranged IgH alleles in T cells share many chromosomal contacts and largely reside in active chromatin. In brain, however, the locus resides in a different repressive environment. We conclude that IgH adopts a lymphoid-specific nuclear location that is, however, unrelated to maintenance of allelic exclusion. We additionally find that in mature B cells-but not in T cells-the distal VH regions of both IgH alleles position themselves away from active chromatin. This, we speculate, may help to restrict enhancer activity to the productively rearranged VH promoter element
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